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What is the purpose of “!” and “?” at the end of method names?
...e object while Enumerable#sort! sorts it in place.
In Rails, ActiveRecord::Base#save returns false if saving failed, while ActiveRecord::Base#save! raises an exception.
Kernel::exit causes a script to exit, while Kernel::exit! does so immediately, bypassing any exit handlers.
Methods ending in ? re...
Python vs Cpython
...mplement new features; Python-the-language development uses CPython as the base; other implementations follow.
What about Jython, etc.?
Jython, IronPython and PyPy are the current "other" implementations of the Python programming language; these are implemented in Java, C# and RPython (a subset of P...
use Winmerge inside of Git to file diff
..." "$(cygpath -aw "$2")"
"$PROGRAMFILES/WinMerge/WinMergeU.exe" -e -ub -dl "Base" -dr "Mine" "$(cygpath -aw "$1")" "$(cygpath -aw "$2")"
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What is href=“#” and why is it used?
...n annoying jump to the top of the page, but in the case of sites using <base>, <a href="#"> is handled as <a href="[base href]/#">, resulting in an unexpected navigation. If any logable errors are being generated, you won't see them in the latter case unless you enable persistent ...
Float vs Decimal in ActiveRecord
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So if I understand correctly, float is in base-2 whereas decimal is in base-10? What would be a good use for float? What does your example do, and demonstrate?
– Jonathan Allard
Dec 15 '11 at 20:30
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What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?
....txt
C:\projects\sandbox\trunk\file.txt
So, getPath() gives you the path based on the File object, which may or may not be relative; getAbsolutePath() gives you an absolute path to the file; and getCanonicalPath() gives you the unique absolute path to the file. Notice that there are a huge number ...
Filter data.frame rows by a logical condition
I want to filter rows from a data.frame based on a logical condition. Let's suppose that I have data frame like
9 Answers...
Image library for Python 3
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You can use my package mahotas on Python 3. It is numpy-based rather than PIL based.
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How to use the 'sweep' function
...a weighted covariance matrix as per @James King's example.
Here's another based on a current project:
set.seed(1)
## 2x2x2 array
a1 <- array(as.integer(rnorm(8, 10, 5)), dim=c(2, 2, 2))
## 'element-wise' sum of matrices
## weights = 1
rowSums(a1, dims=2)
## weights
w1 <- c(3, 4)
## a1[, , 1]...
What is a race condition?
...rent.atomic, concurrent data structures, proper synchronization, and actor based concurrency will help.
The best resource for concurrency is JCIP. You can also get some more details on above explanation here.
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